Nonlinear k-Space Mapping Method for SAR Fourier Imaging

Abstract

A method for nonlinear mapping of k-space samples to facilitate the two-dimensional irregular to regular resampling required by the polar format algorithm (PFA) is presented. Mapping the locations of the collected k-space samples to a uniform rectangular grid and desired locations covering the data region, the interpolation becomes separable in two-dimensions. Resulting PFA images require no further processing to be displayed in the global X, Y coordinates and use all the collected data. This method of resampling allows PFA image formation from bistatic synthetic aperture radar (SAR) and also data collected from irregular flight paths.

Infant Death in Late Prehistoric Southeast Asia

“…In contrast with the other Thai data, the Khok Phanom Di sample had a very high, narrow peak of death occurring around 38-40 weeks. This indicates that a larger proportion of perinates were aged approximately 40-42 weeks, assuming that the standards were underestimating the perinates' age by approximately one or two weeks (Halcrow 2006). This assumption is made based on comparative analysis that has shown Southeast Asian full-term perinates were aged on average one to three weeks younger than their known age when using regression equations based on European perinates.…”

Polar format algorithm based on fast Gaussian grid non‐uniform fast Fourier transform for spotlight synthetic aperture radar imaging

“…In practice, spotlight SAR systems may undergo highly non‐linear flight paths [10–12], to the extent that the model assumption of a rectilinear path no longer holds. This scenario may occur because of various factors such as rugged topography, atmospheric turbulence and intended manoeuvres.…”

EFFECTS OF DIETARY FIBER ON GROWTH, ASSIMILATION AND CELLULASE ACTIVITY OF THE PRAWN (Macrobrachium rosenbergii)1

“…The r o l e o f d i e t a r y f i b e r i n n u t r i t i o n r e s e a r c h i s r e c e i v i n g g r e a t e r emphasis and c e l l u l o s e i s becoming i n c r e a s i n g l y recognized as an import a n t r e s o u r c e because i t i s one o f t h e e a r t h ' s most abundant r e s o u r c e s (Wilke 1 9 7 5 ) . C e l l u l a s e , a n enzyme that degrades c e l l u l o s e , h a s been shown t o be p r e s e n t i n f i s h e s (Stickney and Shunway 1974; P r e j s and Blaszczyk 1977) as w e l l as i n i n v e r t e b r a t e s , which o f t e n p o s s e s s endogenous c e l l u l a s e s i n a d d i t i o n t o c e l l u l a s e s o f m i c r o b i a l o r i g i n (Yokoe and Yasumasu 1964; L e w i s and Whitney 1968;Crosby and Reid 1971;Halcrow 'Contribution N o . 80-16C, S o u t h e a s t F i s h e r i e s Center I N a t i o n a l Marine F i s h e r i e s S e r v i c e , NOAA, C h a r l e s t o n , SC 29412.…”